1. Field of the Invention
The present invention relates to an electrolyzed water production system of the type which includes an electrolytic cell arranged to electrolyze diluted brine prepared by a mixture of raw water and saturated brine of predetermined concentration for producing electrolyzed water.
2. Description of the Prior Art
Disclosed in Japanese Patent Laid-open Publication 7-155764 is an electrolyzed water production system of this kind which includes an electrolytic cell arranged to be supplied with diluted brine prepared by a mixture of saturated brine of predetermined concentration and raw water supplied from an external source of raw water and to be activated by predetermined voltage applied at its electrodes. In the conventional production system, the property of the electrolyzed water is influenced by an amount of saturated brine mixed with the raw water. For this reason, the amount of saturated brine is adjusted by feedback control such that the electric current across the electrodes (or the conductivity of the diluted brine) becomes substantially equal to a predetermined target value.
However, since the amount of the saturated brine mixed with the raw water is always increased from a constant amount under the feedback control when the system is activated to produce the electrolyzed water, the time required to produce the electrolyzed water having a desired property in one system placed in the area where the raw water is hard water is largely different from the time required in another system placed in the area where the raw water is soft water.
In the conventional electrolyzed water production system, an electrically operated fluid pump the discharge amount of which can be easily controlled is used to supply the saturated brine for mixing with the raw water. The fluid pump is in the form of a fluid pump of the pulse driven type which includes a solenoid arranged to be applied with pulse train signals of a predetermined period so that the piston is reciprocated by attractive forces caused by energization of the solenoid. On the other hand, the feedback control is effected by an electrical control circuit of the digital type such as a microprocessor which is programmed to detect a value of electric current across the electrodes at a predetermined interval and to control the discharge amount of the fluid pump in such a manner that the value of electric current is adjusted to the target current value. In such feedback control of the fluid pump, however, the conductivity of the diluted brine is discontinuously detected by the digital circuit and fluctuates since the fluid pump is intermittently operated in response to each pulse applied thereto under control of the digital circuit. As a result, the feedback control is carried out in dependence upon a conductivity different from an average conductivity of the diluted brine, and the supply amount of the saturated brine becomes insufficient or excessive, resulting in irregular production of the electrolyzed water.